The movement of a motor vehicle is defined through actuation of the accelerator pedal, wherein an accelerator pedal sensor, for example, measures the degree to which the accelerator pedal has been pressed and the degree of injection of an injection system, for example, is controlled as a function of the output signal emitted by the accelerator pedal sensor. When the accelerator pedal is not actuated the accelerator pedal sensor normally outputs a zero signal corresponding, for example, to the idle running mode of operation of the motor vehicle. However, if the accelerator pedal sensor outputs a signal or, as the case may be, an accelerator pedal voltage which is greater than zero, even though the accelerator pedal has not been pressed, this leads to the deactivation of monitoring mechanisms, resulting in the inability to detect and avoid unexpected accelerations. This can lead to problems. Deviations of this kind may be attributable to manufacturing tolerances, but can also be due to operating deviations of electrical or mechanical origin. Such deviations of an electrical kind include, for example, intermittent shunt resistances or short-circuits. Deviations of a mechanical type can be based, for example, on the fact that the accelerator pedal no longer returns completely to the neutral position (initial position) due, for example, to material fatigue (in springs, etc.).
In order to rectify the problems described in the foregoing, a learning technique was developed for the purpose of changing the output value (pedal voltage) of the accelerator pedal sensor corresponding to the low-pressure degree of the accelerator pedal from zero (neutral position of the accelerator pedal) to a more suitable value that corresponds to the actual neutral position. In this case the lowest pedal voltage measured in each drive cycle for each pedal track was used for defining the neutral position (idle position) of the accelerator pedal for the remainder of the drive cycle. No transfer took place in this case between different drive cycles. A certain robustness was achieved by ignoring the start phase, i.e. the learning process was not activated until a specific time had elapsed since the starting of the motor vehicle.
However, experience has shown that said learning technique or, as the case may be, adjustment strategy is not sufficiently robust to withstand in particular distortions caused by the aforementioned intermittent shunt resistances or short-circuits and mechanical variations in operation or manipulations.